Processing machine for flat material parts and a support unit thereof

ABSTRACT

A metal-cutting machine for flat material parts comprises metal-cutting tools ( 21, 22, 23 ), held on a machine frame, and a support unit ( 10 ), on which a flat material part to be machined can be placed for a positioning in the metal-cutting machine. The support unit comprises a feed table ( 10 ), which is clamped remote from the beams and on one side about a pivot axis that is pivotable parallel to the beam orientation ( 39 ) and the free end ( 26 ) of which feed table in the parking position rests on a support surface ( 27 ) assigned to the lower beam ( 21 ), which support surface is connected via a sliding surface ( 28 ) to the top side ( 29 ) of the lower beam ( 21 ). The clamped end ( 36 ) of the feed table ( 10 ) is here movable by means of a drive ( 40 ), in the direction of extension ( 45 ), into its loading and removal position, wherein the bottom edge ( 25 ) of the feed table slides from the support surface ( 27 ) over the sliding surface ( 28 ) and beyond the top side ( 29 ) of the lower beam, and the top side ( 29 ) forms the support for the bottom side ( 16 ) of the feed table ( 10 ) in the loading and removal position for a flat material part.

TECHNICAL FIELD

The present invention relates to a metal-cutting machine for flat material parts, comprising a machine frame, a lower beam, an upper beam, at least one metal-cutting tool assigned to the lower beam and held on the machine frame, a control unit for controlling a machining cycle with the metal-cutting tools, and a support unit, on which the flat material part to be machined can be placed for a positioning in the metal-cutting machine, wherein the support unit is movable out of a parking position, in a direction of extension, between the open metal-cutting tools into a loading and removal position and back again, and further relates to a support unit for the same.

PRIOR ART

A metal-cutting machine for flat material parts, which has a machine frame and metal-cutting tools held on the machine frame, is known from EP 1 905 522 A1. Here, a control unit for controlling a machining cycle with the metal-cutting tools is provided. The metal-cutting machine also has a support unit, on which the flat material part to be machined can be placed for positioning in at least one principal direction of feed.

From the brochure “XX1-Center” of RAS Reinhardt Maschinenbau GmbH, dated 06/2012, available under “XXL-Center_75xx-2:d.pdf” on the website of the said company, reference is made to so-called feed tables made of chromium steel, which at the beginning of the bending cycle emerge from the working plane and travel forwards out of the machine. The feed tables here rest on rollers, which move the table surface freely above the lower beam and beneath the upper beam forward and back between these same. The feed table is here moved out to the point where the operator can comfortably load the particular sheet width. As soon as a pedal switch is pressed by the operator, the feed tables draw the sheet into the machine. While the feed tables move back into the machine, stop fingers inside the machine automatically align the fed-in flat material. As soon as the sheet bears against the stop fingers, grippers take over the workpiece.

EP 2 915 604 A1 describes a rear stop for a press brake having a sliding body and an operating contact element, wherein the latter is arranged movably on the sliding body and can move forwards and backwards thereon counter to a spring force.

DE 10 2013 106764 A1 describes a support unit in which, in order to feed between the clamping tools the bending part, not only is it necessary to pivot the pivoting carrier unit about a pivot axis, but it is at the same time necessary, on the one hand, to move by means of the carrier base motion unit, in a manner controlled by the machine control system, the base unit in the direction of feed up to the clamping tools and, on the other hand, to move the pivoting carrier base units in the height positioning direction such that a portion of the bending part, which portion is to be bent, extends in the clamping plane and can thus be placed onto the clamping surface of the lower clamping tool in parallel alignment to the clamping plane E.

EP 0 785 832 B1 discloses a workpiece stop device for a machine tool, comprising a support frame, an adjustment carriage movable in a stop direction on the support frame, and a stop element movable by the adjustment carriage, wherein the stop element has a stop arm, which is provided with at least two stop faces arranged at a distance apart in the stop direction. The stop element can here be brought into a first position, in which a first stop face arranged closest to the machine tool is in the active position, and into a second position, in which a second stop face is in the active position, whilst the stop faces situated on the machine-tool side of the same are in the inactive position.

REPRESENTATION OF THE INVENTION

Starting from this prior art, the object of the invention is to define a simpler support unit for a metal-cutting machine for flat material parts, which is more easily and more accurately controllable, in particular with an electric drive. In addition, a further independent aim of the present invention is to improve the draw-in process of the loaded flat material part. Another objective which is independent thereof lies in increasing the work safety.

The invention provides a support unit for a metal-cutting machine for flat material parts, having the features of Claim 1.

Since the support unit is a feed table, which, remote from the beams, is on one side resiliently clamped about a pivot axis that is pivotable parallel to the beam orientation, and the free end of which, in the parking position, rests on a support surface assigned to the lower beam, which support surface is connected by a sliding surface to the top side of the lower beam, and the clamped end of the feed table is movable by means of a drive, in the direction of extension, into its loading and removal position, wherein the bottom edge of the feed table slides from the support surface over the sliding surface and beyond the top side of the lower beam, and the top side forms the support for the bottom side of the feed table in the loading and removal position for a flat material part, a mechanism with which flat material parts can be loaded in a safe manner with low maintenance can be defined in a very simple manner.

A support surface which is simpler for the operator and which, moreover, allows an automatic adjustment of the flat material part to be machined is proposed.

Advantageously, the feed table is made of a material from the group comprising CDF (compact density fibreboard), as well as the highly compressed and melamine-coated plate material from Kronospan, POM for poloxymethylene, marketed under the name Delrin by DuPont, plates coated on both sides or on one side with synthetic resin and having an appropriate core, wooden boards, medium density fibreboards, brush plates, so-called ball plates, or aluminium plates. The bottom side can then still be advanced sufficiently over the lower beam, but the top side (with the exception of the use of ball plate) is rough enough to draw in the flat material part without slippage when the feed table is retracted. In addition, the control system, upon the start-up of the retraction process, can trigger via a speed increase an acceleration process of the feed table, in which the power feed for the electric motor is performed incrementally, instead of simply switching this on and thus effectively virtually jumping from a zero speed to the end speed.

Apart from a design as a one-piece surface made of a uniform material, i.e. a plate, this can also be of structured composition, insofar as the bottom side is consistently smooth, has a rigid front bottom edge, and the top side allows a flat material part to be placed thereon without snagging. In particular, the table can consist of two mutually fastened, for example bonded together plates, of which the lower plate, which forms the lower corner edge and the bottom side, is smooth, and wherein the lower coating has a smaller coefficient of friction than the upper coating.

The feed table can thus, at least on the top side, consist of a material which enables a frictional engagement. The plate can thus be one-part, two-part with coating, or three-part with core and two mutually opposite, in particular different coatings, wherein the lower coating has a smaller coefficient of friction than the upper coating.

By coefficient of friction is here understood, in particular, the coefficient of friction for the static friction.

The lower plate can here have a coefficient of friction μ in relation to steel of μ<=0.2, in particular if it is made of one of the above-stated materials. The upper plate, which is connected to this lower plate and which forms the top side on which the flat material part is intended to rest, advantageously has a coefficient of friction μ in relation to steel of μ>=0.2.

That end of the feed table which is resiliently clamped about the pivot axis can be realized by at least one leaf spring, which is fastened to the table surface and the other end of which is oriented in the direction of extension and is fastened to an element assigned to the drive. The leaf spring can in this case be fastened, in particular, to the bottom side of the feed table, in particular screwed onto it. The element assigned to the drive here advantageously comprises the profile which is movable back and forth in the direction of extension.

The leaf spring plate can also be of narrow construction and can be fastened to the feed table and to the transportable mounting just with one fastening element respectively. Advantageously, transversely to the axis of movement, two or more such leaf springs are provided. The leaf springs can also be in the form of parabolic springs.

Further embodiments are defined in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below on the basis of the drawings, which serve merely for illustration and should not be interpreted restrictively. In the drawings:

FIG. 1 shows a very schematic side view of, in this case, essential parts of a metal-cutting machine with the support table in a retracted and in an extended position;

FIG. 2 shows the support table according to FIG. 1 with an illustrative embodiment of a suspension mounting and motorized drive means in a perspective view from below;

FIG. 3 shows the circle III of FIG. 1 as a detailed extract with the extended support table;

FIG. 4 shows a detail from FIG. 2 in another perspective bottom view with regard to the fastening of the support table to its frame;

FIG. 5 shows a top view of a further illustrative embodiment of a two-part support table;

FIG. 6 shows an enlarged front view of the front corner of the support table according to FIG. 5; and

FIG. 7 shows an enlarged sectional view along the line VII-VII in FIG. 5.

DESCRIPTION OF PREFERRED EMBODIMENTS

A support unit according to an illustrative embodiment of the invention is designed for use in a metal-cutting machine for flat material parts. Such a metal-cutting machine can be constituted by any known bending machine, in particular, however, it should have at least two stands, generally has three, four or six stands, in order to be able to machine wider sheet-metal parts in the form of flat material parts.

FIG. 1 now shows a very schematic side view of parts, fundamental to the illustrative embodiments of the present invention, of such a metal-cutting machine, with a support unit in a retracted and in an extended position. The support unit is here referred to as a feed table or support table 10, which is likewise illustrated in dashed representation as an extended support table 10′. FIG. 2 shows the support table 10 according to FIG. 1 with an illustrative embodiment of a suspension mounting and motorized drive means, in a perspective view from below. FIG. 3 shows a detailed extract from FIG. 1, with the extended support table 10′, shown in dashed representation, from the circle (labelled with III) from FIG. 1, and FIG. 4 shows a detail from FIG. 2 in another perspective bottom view with regard to the fastening of the support table 10 to its frame.

Of the metal-cutting machine for flat material parts, only the lower beam 21, the metal-cutting tool 22 assigned to the lower beam, and the upper beam 23 are represented, wherein the upper beam 23 is represented in the open state before any clamping of the flat material part (not represented in the drawings). With the reference symbol 10 is denoted the feed table in the retracted position. The reference symbol 10′ has been used for the same feed table (shown in dashed representation) in the extended position. The extension length 35 is chosen such that the flat material can be comfortably loaded by the operator.

From FIG. 1 it can be seen that the plane of the feed table in the extended position 10′ is different from the plane of the retracted feed table 10, in particular because the extended feed table rests with its bottom side 16 directly on the top side 29 of the lower beam 21, whilst the lower front corner edge 25 of the free end 26 of the retracted feed table 10 is positioned on a bearing slope 27 (evident from FIG. 3) of the lower beam 21. The plane of the extended feed table 10′ is slightly inclined by an angle relative to the plane of the retracted feed table 10. The value of the angle substantially corresponds to the tangent of the thickness of the plate of the feed table 10 to the gap between the mounting points of the leaf spring plate 12 on the transverse profile 14 of the inner edge 39 of the lower beam 21 when the feed table 10 is fully extended. This value can amount in radians, for instance, to 1/50, in particular between 1/20 and 1/100, or between 0.5 and 3 degrees. With the reference symbol 47 is indicated the pivot axis, which, at the height of the fastening of the bottom side 16 of the feed table 10 to the transverse profile 14, runs perpendicular to the drawing plane of FIG. 1, and thus parallel to the front corner edge 25 of the feed table 10 and to the inner edge 39 of the lower beam 21.

The direction of extension corresponds to the arrow having the reference symbol 45. The direction of retraction 46 is then the reverse movement. The arrows 45 and 46 are oriented parallel to the top side 15 and bottom side 16 of the feed table 10. Due to the climbing of the front edge 25, the actual physical direction of extension of the feed table during the extension is inclined slightly upwards in a monotonically rising manner and the direction of retraction is inclined slightly downwards in a monotonically falling manner.

A flat material part (not represented in the drawings) which is to be fed in and subsequently machined, following placement on the feed table 10, rests flatly on the top side 15 thereof.

The feed table 10 is fastened solely in the region remote from the beams, i.e. in the direction of retraction 46, to a transverse profile 14 via in this case two leaf spring plates 12. The support unit is thus formed by the feed table 10, which is clamped remote from the beams, on one side about a pivot axis 47 oriented parallel to the beam orientation 39. The leaf spring plates 12 are preferably oriented at a right angle with their longer dimension in the directions of movement 45/46 of the feed table 10. The fastening is realized via a plurality of screws 13, for instance two in the region of the two corners, assigned to the free end 26 of the feed table 10, of the respective leaf spring plate 12. The leaf spring plates 12 are fastened at their opposite corners (not visible in the drawings) to the transverse profile 14 via screws recessed therein. The leaf spring plates 12 are flexible enough to allow a deflection of the table 10 by just a few degrees without here exerting an excessive, abrasive effect on the front corner edge 25.

The transverse profile 14 is fastened at its two free ends to a respective side profile 30 via in each case a mounting bracket 11. The side profile 30 is arranged substantially horizontally beneath the plane of the top side 29 of the lower beam 21. The mounting brackets 11 here possess guide elements (not represented in the drawings), which allows a longitudinal displacement of the mounting brackets 11 on the respective side profile 30 in the direction of the axes of movement 45/46. In the drawing of FIG. 2, two side profiles 30 are provided in bottom view, though in principle it can also be a case of a single profile 30, which can likewise be arranged in the middle of the transverse profile 14.

The mounting bracket 11 is in this case connected, with its element engaging in the guide of the side profile 30, to an electric drive 40, in order to bring the support table 10 into an extended position in the manner shown in FIG. 1, wherein the mounting bracket 11′, in the extended position, is then arranged in the front region of the side profile 30. With this furthest advanced position, the maximal ascending angle of the extended table 10′ is also obtained. An electric drive 40 has the advantage of simple design and of slow start-up in relation to additionally possible hydraulic drives for the displacement of the support table 10.

With reference to FIG. 3, it can be seen that, in the retracted position, the lower front edge 25 of the feed table 10 rests on a bearing slope 27 of the lower beam 21. The arrangement of side profile 30 with rearward position of the transverse profile 14 is correspondingly configured. The top side 15 of the feed table 10 here spans a horizontal plane, which is oriented in line with the top side 29 of the beam 21, so that a flat material to be machined, which lies on the beam 21 and the retracted feed table 10, lies smoothly, flatly and horizontally on these two surfaces.

This bearing slope 27 can have, for instance, an angle between 10 and 30 degrees to the horizontal. This bearing slope 27 extends somewhat further than the retractedly sited feed table 10 in both directions, has, for instance, a length of between 3 and 6 centimetres in the direction of extension 45 and then passes, in the proximity of the beams, into a steeper sliding surface 28, that is to say which has a greater angle of between 30 and 45 degrees, for instance, with respect to the horizontal plane. The length of the sliding surface 28 in the direction of extension 45 can measure between 1 and 3 centimetres and serves to lift the support table 10 out of the region beneath the support plane of the flat material part into the region between the beams 21 and 23. When the top side 29 of the lower beam 21 is reached at the edge 39, the sliding surface 28 then passes into this horizontally arranged top side 29.

The angles of the bearing slope 27 and of the sliding surface 28 can also increase steadily between, for instance, 10 degrees to a value of 45 degrees, and can then pass with a steep drop into the flat (=0 degrees) top side 29 of the beam 21, so that the bearing slope 27 and the sliding surface 28 form a common surface which in cross section is curved into an S-shape.

Upon a forward movement of the feed table 10 in the direction 45 as a result of the forward movement of the mounting brackets 11, the feed table 10 moves slidingly over the bearing slope 27 into the region of the sliding surface 28, and finally the feed table 10 advances into the positioning space of the metal sheet, which positioning space lies in front of the beams 21, 22, 23. Since the feed table 10 is fastened resiliently to the transverse profile 14 about the pivot axis 47 only via the leaf spring plates 12, its free end 26 can extend out of the originally defined plane.

A user of the machining installation can then place a metal sheet onto the top side 15 of the extended feed table 10′, wherein the metal sheet, by virtue of its weight and a frictional engagement, remains in place even when the feed table 10 is moved back in the direction 46 and retreats into the starting position.

Beside the side edges 17 of the feed table 10, on the left and right there is preferably respectively provided a gripper (not represented in the drawings), which grippers are arranged such that they are next to the feed table when this is in its rearward position, so that an end edge (not represented in the drawings) of a flat material placed on the feed table 10 butts against respectively a stop face of an open gripper and this then forms a predefined stop. Preferably, two or more feed tables 10 are disposed with a free space lying between the side edges 17, in order to arrange the grippers in this interspace. In the case of two grippers, a stop line arranged transversely to the direction of extension and parallel to the beam edge 39 is then formed. Advantageously, these grippers are arranged displaceably in a synchronized manner in the direction of extension, in order to form different stop depths for the flat material. Following contact with the stop face, the grippers can be closed automatically or upon a control command and then move the clamped flat material forwards in the direction of extension 45, so as to be clamped by the beams 21 and 23 and bent by the tool 22. The stop elements can also be provided, however, in positionally fixed arrangement.

In particular, the control unit (not represented in the drawings) can execute a multi-step process: Firstly, the feed table 10 is extended and the process for a manual handling by the user is interrupted. Following a feed-in of a flat material piece, which is detected by sensors and can be reported to the control unit, the feed table 10 is retracted and the prespecified and preprogrammed bending steps are executed. After this, the feed table is newly extended, either for the removal of the flat material or for a further interruption and a manual handling of the then extended flat material by the user. This handling can include a tipping, rotation or turning. In the course of the tilting, the flat material is rotated through 180 degrees about its bending axis, so that the previously outer flat material portions are now situated on the inside. In the course of the rotation, the flat material is rotated through 180 degrees about the vertical axis, so that the top side here also ends up at the top. Finally, the manual handling can also comprise the turning, in which the rotation and tilting is combined. Following completion of the manual handling by the user, the interrupted machining operation is taken up again by a resumption command to the control unit.

FIG. 5 shows a top view of a further illustrative embodiment of a two-part support table 10. This consists of a lower base plate 50 made of sheet metal, in particular a CNS (chromium-nickel-steel) sheet metal. Into this plate are sunk boreholes 51, through which the screw head of screws which connect a free end of a resilient element, in particular a leaf spring, in a screw-tight manner to the support table can be actuated, so that, as a result of the fastening to a transverse profile of the apparatus, this free end allows an inclination of the base plate 50 out of the drawing plane of FIG. 5. The holes 52 then offer a free space for the mounting screws for fastening the resilient element to the transverse profile.

Not visible in FIG. 5 is that the sheet metal of the base plate 50, at the sides 57, is bent over downwards in the direction of the sheet of the drawing.

In FIG. 6 is now shown an enlarged front view of the front corner 90 of the support table 10 according to FIG. 5; and FIG. 7 shows an enlarged sectional view along the line VII-VII from FIG. 5.

At the, in FIG. 5, upper edge of the base plate 50 made of steel plate, the short edge 57 covers a slide plate 60 made of CDF (compact density fibreboard) material. The slide plate 60 can here also be produced from a different material with good sliding characteristics and high stability. More generally speaking, the top side of the support table is formed by a base plate 50, which has a higher coefficient of friction than the lower slide plate 60 and/or advantageously a lower wear value.

On that side which is facing the top side 15 of the feed table 10, the sheet-steel base plate 50 of L-shaped cross section covers the CDF material in the form of a slide plate 60. There is a short edge 57 of the steel plate which is shorter than the thickness of the CDF slide plate 60, so that it surrounds this slide plate 60 like an apron, and advantageously accompanies all four sides and, in particular, the two opposite long side edges of the slide plate 60. The short edge 57 has a height which is smaller than the thickness of the slide plate 60, so that the edge 57 does not protrude over the bottom side 16.

In FIG. 6 it can be seen that the rounded bearing end 56 of the base plate 50 nestles against the outer side of the CDF slide plate 60. The reason for this is that the steel plate 56 does not scrape, but rather the unit glides on the CDF edge 64. The side edge 57 of the sheet-metal plate 50 covers a large part of the slide plate 60 like an apron.

The feed table slides on the CDF edge 64 on the bottom side 16, which is then advanced and also climbs the lower beam 21. On the opposite side, i.e. the top side 15, can be seen a bevelled front edge 54 of the base plate 50, in order that the sheet does not get caught in the course of its insertion and no sharp edges exist when the table is out within the working range of an operator feeding a sheet to be machined, so as to minimize the risk of injury.

The relationship of the characteristics between base plate 50 and slide plate 60 is chosen such that the slide plate 60 has better sliding properties than the base plate 50, but the base plate 50 has better rigidity and abrasion resistance than the slide plate 60.

The permanent connection between the base plate 50 and the slide plate 60 is achieved by adhesive 82, which is provided in grooves 80 arranged in the direction of advance 45. Given a width of the base plate 50 of 864 millimetres combined with a width of the slide plate of 862 millimetres (thickness of the metal sheet of the base plate 50 equal to 1 millimetre), five such grooves 80 provided over the entire length of the slide plate 60 and having a width of 25 millimetres and a depth of 2.5 millimetres can be provided in the slide plate 60, which, with a thickness of 12.5 millimetres, is still sufficiently thick. The adhesive can be a polymer assembly adhesive. At least two such grooves 80 should be provided. They could also be arranged transversely, even though the longitudinal arrangement is preferred.

In FIG. 7 can further be seen a borehole 51, which in the metal sheet 50 is provided with a diameter which is larger than a screw head which is to be inserted into the slide plate 60. Through this opening in the metal sheet 50, the screw head of screws which reach into the one free end of the said resilient element, in particular a leaf spring, wherein the free end is thus connected in a screw-tight manner to the support table 10, can be actuated, so that, by the fastening of the other free end to a transverse profile of the apparatus, it allows an inclination of the base plate 50 out of the drawing plane of FIG. 5. The holes 52 according to FIG. 5 in the slide plate 60, having a considerably greater diameter, then offer a free space for the mounting screws for fastening the resilient element to the transverse profile.

REFERENCE SYMBOL LIST 10 feed table, retracted 10′ feed table, extended 11 mounting bracket, retracted 11′ mounting bracket, extended 12 leaf spring plate 13 screw 14 transverse profile 15 feed table top side 16 feed table bottom side 16′ bottom side, extended feed table 17 feed table side edge 21 lower beam 22 metal-cutting tool 23 upper beam 25 front corner edge 26 free end 27 bearing slope 28 sliding surface 29 lower beam top side 30 side profile 35 extension length 36 clamped end 40 electric drive 45 direction of extension 46 direction of retraction 47 pivot axis 50 base plate (steel sheet) 51 screw hole 52 holes 54 bevelled lower edge 56 rounded bearing end 57 short edge of the sheet 60 slide plate (CDF material) 62 lateral bevel of the slide plate 64 front bevel of the slide plate 80 groove 82 adhesive 90 front corner enlargement 

1. Metal-cutting machine for flat material parts, comprising: a machine frame, a lower beam having a thereto assigned support surface, which is connected via a sliding surface to the top side of the lower beam, an upper beam, at least one metal-cutting tool assigned to the lower beam and held on the machine frame, a control unit for controlling a machining cycle with the metal-cutting tools, and a support unit, on which the flat material part to be machined can be placed for a positioning in the metal-cutting machine, a drive connected to the support unit, at least one spring, with which the support unit is connected to the drive, wherein the support unit is movable by the drive out of a parking position, in a direction of extension, between the open metal-cutting tools into a loading and removal position and back again, wherein the support unit, remote from the beams, is on one side resiliently connected to the drive about a pivot axis that is pivotable parallel to the beam orientation, wherein a free end of the support unit in the parking position rests on the support surface assigned to the lower beam, wherein a clamped end of the receiving unit is movable by means of the drive, in the direction of extension, into its loading and removal position, wherein the bottom edge of the support unit slides from the support surface over the sliding surface and beyond the top side of the lower beam, and the top side forms the support for the bottom side of the support unit in the loading and removal position for a flat material part.
 2. Metal-cutting machine according to claim 1, characterized in that that end of the support unit which is resiliently clamped about the pivot axis is realized by at least one leaf spring fastened to the table surface, the other end of which leaf spring is oriented in the direction of extension and is fastened to an element assigned to the drive.
 3. Metal-cutting machine according to claim 2, characterized in that the leaf spring is fastened to the bottom side of the support unit, and in that the element assigned to the drive comprises a profile which is movable back and forth in the direction of extension.
 4. Metal-cutting machine according to claim 3, characterized in that the leaf spring is screwed onto the bottom side of the support unit.
 5. Metal-cutting machine according to claim 1, characterized in that the support surface is a surface ascendingly inclined relative to the beam top side in the direction of extension, and in that the sliding surface is a surface ascendingly inclined relative to the beam top side in the direction of extension.
 6. Metal-cutting machine according to claim 5, characterized in that the ascendingly inclined surface of the support surface has in the direction of extension an angle between 10 and 30 degrees to the beam top side, and in that the ascendingly inclined surface of the sliding surface has in the direction of extension an angle between 30 and 45 degrees to the beam top side.
 7. Metal-cutting machine according to claim 5, characterized in that the support surface has in the direction of extension a width between 3 and 6 centimetres, and in that the sliding surface has in the direction of extension a width between 1 and 3 centimetres.
 8. Metal-cutting machine according to claim 1, characterized in that the support unit is a one-piece plate produced from a homogeneous material.
 9. Metal-cutting machine according to claim 1, characterized in that the support unit is a plate composed of at least two planar plates, of which the lower plate, which forms the lower corner edge and the bottom side of the support unit, has a coefficient of friction in relation to steel which is smaller than the coefficient of friction of the upper plate, which forms the top side of the support unit, in relation to steel.
 10. Metal-cutting machine according to claim 9, characterized in that the at least two planar plates are all bonded together.
 11. Metal-cutting machine according to claim 9, characterized in that the corner edge and bottom side of the plate forming the support unit has a coefficient of friction μ in relation to steel of μ<=0.2, and in that the upper plate, which forms the top side of the support unit, has a coefficient of friction μ in relation to steel of μ>0.3.
 12. Metal-cutting machine according to claim 9, characterized in that the support unit comprises a core, and a lower coating forming the lower plate and an upper coating forming the upper plate, wherein the lower coating has a smaller coefficient of friction in relation to steel than the upper coating in relation to steel.
 13. Metal-cutting machine according to claim 9, wherein the coatings are synthetic resin coatings.
 14. Metal-cutting machine according to claim 9, characterized in that the upper plate is made of steel.
 15. Metal-cutting machine according to claim 9, characterized in that the lower plate is made of a material from the group comprising CDF (compact density fibreboard), melamine-coated plate material, POM (poloxymethylene), wood, MDF, so-called brush plates, or aluminium.
 16. Metal-cutting machine according to claim 1, characterized in that the support unit is a so-called ball plate.
 17. Metal-cutting machine according to claim 1, characterized in that the control unit is designed to issue to the drive or drives of the support unit control commands to move the support unit out of the parking position, in a direction of extension, between the open metal-cutting tools into a loading and removal position, so as subsequently to interrupt the dispatching of control commands for a manual handling by the user, wherein the end of the manual handling, which consists of the group comprising the feed-in, the removal, the tilting, the rotation or the turning of the flat material piece, following a positioning of the said flat material piece on the support unit, is either detected by sensors and reported to the control unit or is triggered by a stop switch signal, after which further control commands are issued by the control unit to retract the support unit and to execute pre-specified and/or pre-programmed bending steps, which end with an extension of the support unit, in order to be ready either for the removal of the flat material piece or for a further interruption and a further manual handling.
 18. Support unit for a metal-cutting machine, comprising a feed table clamped remote from the beams and on one side, wherein the clamped end of the feed table is movable by means of a drive in a direction of extension oriented transversely to the clamping direction, wherein the clamped end of the feed table is realized by at least one leaf spring fastened to the table surface of the feed table, the other end of which leaf spring is oriented in the direction of extension and fastened to an element assigned to the drive. 